Testing system



1,49559? K. s. JOHNSON TESTING SYSTEM /nvenfarx /femvef/v 5. Jabnsan.

Patentel May 27, 1924.

tor-Fica.

KE'NNETH S. JOHNSON, OF JERSEY CITY, NEW JERSEY, ASSIGI\OR T0 WESTERN ELEG- TBIC COMPANY, INCOBPGRATED, Oli YORK.

NEW YORK, N. 1., A COR-ZE'ORA'IFIOIT. or NEW TES'IING SYS TEM.

Applicationfiled January 16, 1920. Serial No. 351,943.

T0 aZZ w7zom it mag aoncern.

Be it known that I, KENNETH S. JOHNSON, a oitizen of the United States. residing at Jersey City, in the county of Hudson and State of New Jersey, have invented certain new and useful Improvements in Testing Sytems, of which tbe following is a full, clear, Concise, end exact description.

This invention re1ates to testing systems, and more particularly to systems for the testing of electric signaling end telephone systems.

The principal object of the invention is to provide a testing system in Which matter being transmitted over the lines of a signa1- ing system is not transmitted to tbe test observing apparatus. In accordance With this fe ature of the invention, 1neans are interposed in the testing circuit which prevents the transmission of signaling; current from the signaling system to the test observing or indicating apparatus while providing for the transrnission of testing cnrrent thereto.

Another object of tbe invention is to provide a testing system which will not interfere with the transmission of signals over 1ines conneoting two stations during-testing. In accordance with this featnre of the invention, the testing current applied to the lines is of such a 1ow strength that it does not materially interfere with signaling over 1ines during the testing operation; the test ing current being snbsequently mnplified to a degree snob tbat its presence is readily detected either by an observer or by suitnble antomatic indicating or recording means.

Otber objects end features of the invention not specifically mentioned above will be apparent in the following specification and from the appencled claims.

The drawing shows diagrarnrnatcally one form of the invention es applied to a testing system for -an eutomatic 02111 distributing telephone system I In this embodinnent of the invention a subscribers station A is shown in telephonic communication with station B through the medium of an autorntatc line finder switch LF and its associated automatic cord selector switch CS together with a cord circuit 10 with its p1ug l1-and the jack 12 01 sta.- tion B. The details of how this connection is establishec1 form no part of the present invention end refrence is 111%).(1610 the copend1ng application Serial No.' 275,074 of S. B. Williams, Jr., end H. L. Bostater, fileo1 2 Februa.ry 5, 1919, Patent No, 1,445,258,

21 is intended to be inserted into a tone jack 22 for the purpose of impressing testing our rent on the cord circuit and its associated apparatus t0 facilitate the location of the line finder involved and'from this the particular line in trouble. As more fu11y desoribed in the, VVilliams-Bostater patent applioation previously referred to, a testing contact bank 23 is provided with a number of pairs of test terminals, each 1ine finder having an individual pair allotted thereto and the terminals of each p.air being (3011119011- ed t0 tbe tip end ring; brushes of the brush sets of their respective line finders. The brush set 24 is designed to pass over this contact bank and to successively engage these sets of contacts. The number of the line finder Whose test terminals ere engaged at any time is denoted by the number on the designation strip 25 associated with the benk 23 as indicated by apointer 26 movable with the brushset 24.

The testingcontact bank 23 With its brush set 24 is preferablylocated atan observers position. F0r testing, an observers' set 27 having its receiver 28 and transmitter 29 connected respectively between the sleeve end tip contaots of the plugs 30 and3lis provided end in testing these plugs are insert-- ed into the jacks 32 and 33 respectively.

A tone generator 36 is providec1 to supply testing current for testing operations; and 2L transformer 37 having a primary winding included inthe output circuit 01 the generator 36 is also provideh, the secondary' to the observer ancl thus renders the detection of testing currents possible with a minimum of efl'ort.

he flO-W of testing current in parallel through the right-hantl winclings of the repeating coil in corcl eirouit 20 incluces corresponcling currents of like frequenoies in the lelt-hanrl irindings of this coil. Testing current. is acoordingly present on both tip ancl ring: concluctors f the cord circuit 20, the C01Cl selector 05%, the line fincler LF ancl on the test terminals of this line finder in the contaet bank 23. On the brush set 24: engaging these terminale, an operative eircuit is eo1npletecl extencling from ground ed battery ancl lower lett-hand winding of the repeating coil of corcl cironit 20, the ring contacts of the cor-cl circuit ancl brush set of corcl selector CS, ring test terminal of the associatecl line fincler LF in bank 23 and ring contact of brush set 24:, right-haiad winrling of transformer 42, the impedence coils 4L oonclenser 57, tip contact of brush set and tip test terminal ofthe line fincler LF in bank 23, tip contacts of the brnsh set of the CO1Cl seleotor CS antl corcl circuit 20 and. the upper left-hancl wincling of the repeating coil of this oorcl oircuit to ground. The testing current i1npressed upon the corcl circuit is preferably or" lOW value in orcler to prevent the creation, due to inducti"e actioni of correspondingly flnctuating currents of suflcient strerrgth to interfere with eflicient signaling connnunication over neiglib0iing cord eircuits. The current fl W- ing over the testing oirouit alcove traoecl being o;t testing frequency (below 150 cycles per seconcl) is freely transmittecl to the right-hancl wincling of the transforrner 42 by the elect-rical filter and in traveising th'is Wincling procluoes corresponcling; cnrrent variations in the input oircuit of the amplifier 43. This amplifier in response thereto clevelopes corresponclingr current finotuations of increased amplitucle in the output oircuit thereof Whicl1 in traversinp; the right-hancl wincling et transfonner 54 induce like fluctuations in the circuit including the left-hancl wincling of this transfo1mer ancl the receiver 28 of the observers set. These latter fluotuatins aretranslated by the receiver 28 into sound of a freqnency corresponcling to that of the ourrent developecl by the testine generator 36 and the pro'tluetion of this charaoteristi sound inrliCates to the observer that the brush set 24. is in engagement With the test terminals of the particular line fintler at tl1at time associatecl with the corcl circnit 20 upon whioh testingcurrent has been impressed, as previousl v notecll The pointer 26 is opposite tl1e numeral 3 on the designationstrip at this time ancl thus inclioates that line fincler 8 (clesignatecl as LF on the clrawing) is the one-inv0lvecl in the connecton. IIaving ascertainetl the particular line finder concernecl, th1s.hne fincler 1s v1s1tecl and the set et lune ternnnals thereot engaged by the brush set of. the line fincler notecl.- Fronr this the partieular line inrolvecl in theconnection can be reaclily determinecl, after Which such line is crinclitioned soas to test in trouble ancl the line fincler LF restored to normal position ready for subsequent use With otl1er lines having their contacts in.

the terminal bank of. such line finder.

, In the particular systexn illustratecl,the

restoration of the line finder LF also effects the restoration ot' the associatecl cord selector CS to nonnal and the operation of the clisco1inect signal (not shovvn), as clescribecl in the Villiams-Bostater patent application previotisly mentionecl. The operation of tl1is disoonnect signal serves to indicate to the operator that the trouble has been clearecl and the operator thereupon- 43. The opening of these oircuits preventsclrain upon the current supply sources exeept at suoli tnnes as the system 1s .1n use for testing purposes. Upon complet1onof this operation by the observer,the testing system is in normal condition ready for; sub-. sequent use as occasion demands.

The arrangernent herein set forth is inf tended as merely illustrative of the present invention, which is not li1nitecl to the precise cletails set fort h except as required by the olaims formin,g a part hereof.

Vhat is clai1necl is:

1. A testing; syste1n comprising a plurality of. lines usecl tor signaling connnnnioa; tion, a source of fluetuating; testina current having a certain frequency range, means to clevelop signaling currents for transmission.

over the lines having a freqnency range exclusive of that of the testing current, .an eleetroresponsive test observing devic, an electricalcircuit connection to associate the de'viee with the lines to be teste/cl, and electrical. 1neans incluclecl in such oonnection op-.

erable to prevent the transmission of current wrth1n the signalingr frequency range to the clevice While perinittin transmission of cur-.

rents within 'the testing thereto.

2. A testing systen1 comprising a plurality of lines used for signaling communiation, a

frequency range &

source of flnctnating testing current having a eertain frequeney range, n1eans to develop signaling ourrents or transmssion over the linee havng a reqnency range exclnsve ol tlrat of the testing eurrent an eleetroresponsve test observng cleviee an eleetrical cir= vcnit connection to associate tl1e cleviee with the linee to be testecl, ancl an electrical. frequeney filter inclncled in sncl1 connection operable t0 premnt the trans1nsson 0' cur rents wthn the sgnaling frequeney range to che device while permitng the transrnission of eurrents within the testng frequeney range thereto. y

3. A testing syste1n comprising a pluralty of linee used for sgnalng eornmnnicaton, a sonrce 0f fiuetnating testing enrrent havng a eertain. frequency range, means to develop sgnalng cnrrents f0r transxnission over the linee havng a frequency range in exeess of that of the testing enrrent, an electrorespo1r sive test observng tleviee, an eleetreal circnit conneeton t0 associate the cleviee Wlll1 the linee to be tested, and an electrcal freqneney filter nclucled in snch connecton operable to prevent the transmssion of eurrent 0f freqnencies in excess of the requency range of the testing current to the devce while permitting the transrnisson 0f eurrents Witl1in the testing reqnency range thereto.

4. A testng syste1n comprisng a plurality 0f linee nsetl for telephone commnncation, a source of fiuctuatng testing current hav ing a certain frequency range 1neans to clevelop telephonic currents f0r transmssion over the linee having a freqnency range exelusive of that of the testing current, an electroresponsve test observing devce, an electrcal circnt conneetion to associate the device wth the linee to be testecl, and an electrcal frequency filter included in suole connecton. perable to prevent the transmission. 0f eurrents within the telephone frequency range to the clevce while penntting the transrnission of enrrents within the testng frequency range tlnereto.

5. A testng system cmnprsng a pluralty of lnes nsecl f0r sgnaling connnuncaton, a source of fluctnating testing eurrent having a eertain -Ereqneney range, 1neans t0 develop fiuctnating sgnaling cnrrents for transmsson. over the linee having a freqneney range exclnsve of that of the testng enrrent, means t0 seleetvely supply testing cnrrent to the linee an eleetroresponsive test observing clevce, an electreal crcut eonnectien 0r eleetrcally associating tl1e device and the linee, xneans to seleetfiely associate sueh connecton With the linea and an electr'eal frequency filter included in sueh eonneetion operable to prevent the trans1nssion of current within the signaling frequency range to the device while permttng transmisson o currents wthin tbe teetng requeney range thereto.

6. A testng system comprising a plnrality 0l' subscrbers statione, a plurality 01" link circuts cornrn0n to the statons ancl inclivirlnally operable to establish a telephonie crcuit between tWo 0' the snbseribers stations, a source of flnetuating testng enrrent having a certain requency range, means in a telephonie circuit thns establshed te develop fluctnatng telephonie c:urrents l1aving a freqnency range exclnsve of that of the testing eurrent, 1neans t0 selectvely apply sacl testing cnrrent to the link circuits, an electroresponsve test observng clevice, an electrical circut conneeton tor assoeiating the clevice and the link circnts, means te selectively associate snch conneetion. wth the link circnits, an an electrieal reqnency filter in sueh connection operable to prevent che transnnission 0E enrrents Wihin the telephonc freqneney range to the clevice when such connection s associated with any otf the link circnits wl1ile permitting the trans1nission of cnrrents withn the testng frequeney range to the device.

7. A testng systenn comprising a plurality of adjacent lnes nsecl for sgnalng eon1 muncaton, a sonrce or" flnctuating testing cnrrent havng a certain frequency range and of such low eurrent valne as to be wthout substantal incluctive effect on lines atljacent to a line te which the testing cnrrentis appled, 1neans to selectively apply the sonrce of testng cnrrent to the linee, meane to clevelop sgn aling current f0r transmisson over the lines havng a freqneney range exclusve 0{ tl1at 0'' the testing current, an elec troresponsve test observng clevice,an elestrieal crcnt connection to seleetively assocate the elevice With the lnes an eleetrical requency filter operable to prevent tbetransmisson .of cnrrens witbin the signaling freqnency range While permitting the '2LHSITIS* sion of eurrents wi.thin the testing freqnency range, ancl a current amplifier, che filter and the a1nplifier being both nelncled in the circnit c-onnection and the amplfier serving to snpply amplfieol testng cnrrent to che test observing devce.

8. A testng system comprsng a pluralty of adjacent linee usecl for signali1g comrnnnieation, a souree 0f testing cnrrnt of such lOW current valne as to be without substantal nclnctve efieet upon linee acljacent a line t0 which saicl testing current is applied, means to conneet the source of testing eurrent wi th any clesirecl one of the linee, ari electroresponsve test observng devce, an electrical crcuit conneeton to inclividually associate the devce with the linee, ancl a current amplifier in the connecton to supply amplified testng current to the test observ ng device upon assocaton of the connee llll ity of subscribers stations, a plurality of acljacent link circuits common to the stations ancl indivdually operable to establish a telephonic circuit betvveen two of the subscribers stations, a SOUI'Ce of testing current of such 10W current value as to be without substantial incluct-ive effect upon link circuits adjacent a link circuit to which such testing cu1rent is applied, means no connect the source of testing current with any desired one of the link circuits, an electroresponsive test observing device, an electrical circuit connection to ndividually associate the device with the link circuits, and an electrical current amplifier in the connection' so supply amplified testing current to the testing observing device upon association of the connection with the line to which the source of testing current is connectel.

10. A testing system comprsng a source of fluctuating testing current having a certain frequency range, a pluralit-y Of lines used for the transmission of a current frequency exclusive of that of the testing current, un electroresponsive test. observng device, an electrical circuit connection to associ-ate the device with lines 130 be tested, an electrical frequency filter included in such connection operable to prevent the transmission of currents othe last named frequency to the clevice while permitting the transmission of currents within the testing frequency range thereto, ancl means to amplify the currents within the testing frequency.

11. A testing system comprising a plurality of adjacent lines used for signaling cornrnunication, a source of testing current, a test observing device, an electrical circuit connecton to selectively associate the device with said lines, a filter operable to prevent che transmission of currents other than those ivithin che testing range, and a current ani-v plifier, the filter and the amplifier being both included in che circut connection and the amplifier serving to supply amplified testing current to the. test observing device.

12. A testing system comprising a plurality of subscribers lin'es, a plurality of link circuits common to sad lines and operable to establish connection between tw0 of said lines, a source of testing current, means to co-nnect the source of testing current with any one of said link circuits, a test observing clevice, un electrical circu it connection to associate said device with sad link circuits, ancl an amplifier in the connection to supply amplifiecl testing current to the test observing clevce upon association of the connection with the link circuit to which the source of testing Cuirent is connecced.

13. In 2111 electrical testing system, telephone lines, means for transmitt-ing talking current over said lines, means, for applying a testing current of low cnrrent value to said lines, a, dete,cting circuit including a filter for rejecting said talking current and aclmitting saicl testing current and ncluding means for Subsequently amplif'ying said testing current, ancl electroresponsive apparatus for detecting said amplified current.

14. In an electrical testing system, telephone lines, means for transmitting talking current over said lines, means fo1 applying a testing current 0-f low value to saicl lines, a detectng circuit including a filber for rejecting said talking current and admitting saicl testing current and including a vacuum amplifier for increasing che strength of said testing current, and a telephone recever fo1 cletecting sad amplifiecl testing current.

15. In an electrical testing system for telephone lines, a plurality of lines means or transmittng telephonic current over saicl lines, means for applying a testing current of lowvalue to said lines while telephonic Current is being transmitted thereover, mean-s for subsequently amplifying said testing current, a cletecting circuit including a filter for rejecting sad telephonic current and admitting sad testing current, and electroresponsive apparatus for detecting saicl amplified testing current.

In witness whereof', I hereu1ito subscribe my name this 13th day of J anuary A. D. 1920.

KENNETH S. J OHNSON. 

